Abstract

Introduction: Various agents have been studied to observe the effects on flap viability, necrosis and the wound healing. Sildenafil citrate is a phospodiesterase type 5 enzyme inhibitor, which increases cGMP levels, is used generally in the treatment of the erectile dysfunction. However, the decrease of the capability of thrombosis is maintained by the sildenafil citrate. It is also used for the treatment of the pulmonary hypertansion as a vasodilator agent. We investigated the effect of the sildenafil citrate on the flap viability and the appropriate doses applied.

Materials and Methods: In our study, we used 30 female rats (250- 260 gram). Following ketamine anesteshia, the random flap, 6x2 cm in diameter, was dissected from the dorsal region and sutured onto the same area. A total of 6 groups were formed. The local sildenafil citrate (Sildegra®) injection was applied to the base of the flap in 4 groups with the doses of 0.1, 0.3, 0.5 and 0.7 mg/kg daily during a week. After that, the viability of the flap was evaluated by the drawing necrosis area on a clear paper and histopathologic examination was performed. The statistical analysis was studied with the one-way variance analyze and t- test, using the SPSS for Windows.

Results: The rate of the flap viabilities were 69.2%, 70.38%, 67.28%, 88.66%, 92.16% and 72.84% in control group, sham group, 0.1, 0.3, 0.5 and 0.7 mg/kg groups, respectively. We determined 0.5 mg/kg dose of topical sildenafil citrate most efficient on flap viability.

We confirmed less necrotic tissues and inflamation in 0.3 and 0.5 mg/kg sildenafil flap groups than the others. Neovascularization and the vasodilatation were much more evident. However, in control and sham group, diffuse inflamatory reaction, bleeding and necrotic tissues were observed. The viability of the flap in 0.3 and 0.5 mg/kg sildenafil groups were statistically significant, compared with the control group (p<0.0001).

Conclusion: The range of 0.3-0.5 mg/kg topical sildenafil citrate injection to the base of the random skin flap are the most effective doses to increase and ensure the flap viability. In addition, this appropriate dose range is also clinically accepted and may lead a new investigation about the flap viability, combined with other agents.